Type coercion in operations in PHP - Step-by-Step Execution

Concept Flow - Type coercion in operations

Start with operands

↓

Check operand types

↓

Apply type coercion rules

↓

Perform operation with coerced types

↓

Return result

PHP checks operand types, converts them if needed, then performs the operation and returns the result.

Execution Sample

PHP

<?php
$a = "5" + 3;
echo $a;
?>

Adds a string '5' and an integer 3, showing how PHP converts string to number before addition.

Execution Table

Step	Operands Before	Type Coercion	Operands After	Operation	Result
1	"5" + 3	String '5' converted to int 5	5 + 3	Addition	8
2	Result stored in $a	No coercion needed	$a = 8	Assignment	8
3	echo $a	Output integer 8 as string	8	Output	8

💡 Operation ends after echo outputs the result.

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
$a	undefined	8	8	8

Key Moments - 2 Insights

Why does PHP convert the string "5" to a number before adding?

PHP automatically converts strings to numbers in arithmetic operations, as shown in execution_table row 1 where "5" becomes 5 before addition.

What happens if the string cannot be converted to a number?

If the string does not start with a number, PHP converts it to 0 before the operation, similar to the coercion step in execution_table row 1.

Visual Quiz - 3 Questions

Look at the execution table, what is the result after step 1?

A "5"3

B 53

C 8

D Error

💡 Hint

Check the 'Operands After' and 'Result' columns in step 1 of the execution_table.

At which step does PHP convert the string to an integer?

A Step 1

B Step 2

C Step 3

D No conversion happens

💡 Hint

Look at the 'Type Coercion' column in the execution_table.

If the string was "abc" instead of "5", what would be the result after addition?

A "abc3"

B 3

C Error

D 0

💡 Hint

Recall PHP converts non-numeric strings to 0 before arithmetic, as explained in key_moments.

Concept Snapshot

PHP automatically converts operand types in operations.
Strings with numbers convert to integers or floats.
Non-numeric strings convert to 0.
Operations then proceed with coerced types.
Result is returned in the expected type.

Full Transcript

This example shows how PHP handles type coercion in operations. When adding a string containing a number to an integer, PHP converts the string to a number first. The code adds "5" and 3. PHP converts "5" to 5, then adds 3 to get 8. The result 8 is stored in variable $a and then printed. If the string cannot be converted to a number, PHP treats it as 0. This automatic conversion helps PHP perform operations smoothly even with mixed types.